Methods and devices for treating tissue

ABSTRACT

The invention provides a system and method for achieving the cosmetically beneficial effects of shrinking collagen tissue in the dermis or other areas of tissue in an effective, non-invasive manner using an array of electrodes. Systems described herein allow for improved treatment of tissue. Additional variations of the system include array of electrodes configured to minimize the energy required to produce the desired effect.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/676,243 filed Feb. 16, 2007, which claims benefit of priority to U.S.Provisional Application No. 60/829,607 filed Oct. 16, 2006, the contentsof both of which are incorporated by reference herein in their entiretyfor all purposes.

BACKGROUND OF THE INVENTION

The systems and method discussed herein treat tissue in the human body.In a particular variation, systems and methods described below treatcosmetic conditions affecting the skin of various body parts, includingface, neck, and other areas traditionally prone to wrinkling, lines,sagging and other distortions of the skin.

Exposure of the skin to environmental forces can, over time, cause theskin to sag, wrinkle, form lines, or develop other undesirabledistortions. Even normal contraction of facial and neck muscles, e.g. byfrowning or squinting, can also over time form furrows or bands in theface and neck region. These and other effects of the normal agingprocess can present an aesthetically unpleasing cosmetic appearance.

Accordingly, there is well known demand for cosmetic procedures toreduce the visible effects of such skin distortions. There remains alarge demand for “tightening” skin to remove sags and wrinklesespecially in the regions of the face and neck.

One method surgically resurfaces facial skin by ablating the outer layerof the skin (from 200 μm to 600 μm), using laser or chemicals. In time,a new skin surface develops. The laser and chemicals used to resurfacethe skin also irritate or heat the collagen tissue present in thedermis. When irritated or heated in prescribed ways, the collagen tissuepartially dissociates and, in doing so, shrinks. The shrinkage ofcollagen also leads to a desirable “tightened” look. Still, laser orchemical resurfacing leads to prolonged redness of the skin, infectionrisk, increased or decreased pigmentation, and scarring.

Lax et al. U.S. Pat. No. 5,458,596 describes the use of radio frequencyenergy to shrink collagen tissue. This cosmetically beneficial effectcan be achieved in facial and neck areas of the body in a minimallyintrusive manner, without requiring the surgical removal of the outerlayers of skin and the attendant problems just listed.

Utely et al. U.S. Pat. No. 6,277,116 also teaches a system for shrinkingcollagen for cosmetically beneficial purposes by using an electrodearray configuration.

However, areas of improvement remain with the previously known systems.In one example, fabrication of an electrode array may cause undesiredcross-current paths forming between adjacent electrodes resulting in anincrease in the amount of energy applied to tissue.

In another example, when applying the array to tissue, the medicalpractitioner experiences a “bed-of-nails”. In other words, the number ofelectrodes and their configuration in the array effectively increasesthe total surface area of the electrode array. The increase in effectivesurface area then requires the medical practitioner to apply a greaterforce to the electrode array in order to penetrate tissue. Such adrawback may create collateral damage as one or more electrode may beplaced too far within the skin. Additionally, the patient may experiencethe excessive force as the medical practitioner increases the appliedforce to insert the array within tissue.

Thermage, Inc. of Hayward Calif. also holds patents and sells devicesfor systems for capacitive coupling of electrodes to deliver acontrolled amount of radiofrequency energy. This controlled delivery ofRF energy creates an electric field that generates “resistive heating”in the skin to produce cosmetic effects while cooling the epidermis toprevent external burning of the epidermis.

In such systems that treat in a non-invasive manner, generation ofenergy to produce a result at the dermis results in unwanted energypassing to the epidermis. Accordingly, excessive energy productioncreates the risk of unwanted collateral damage to the skin.

In view of the above, there remains a need for an improved energydelivery system. Such systems may be applied to create improvedelectrode array delivery system for cosmetic treatment of tissue. Inparticular, such an electrode array may provide deep uniform heating byapplying energy to tissue below the epidermis to causes deep structuresin the skin to immediately tighten. Over time, new and remodeledcollagen may further produce a tightening of the skin, resulting in adesirable visual appearance at the skin's surface.

SUMMARY OF THE INVENTION

The invention provides improved systems and methods of systems andmethods of achieving the cosmetically beneficial effects of using energyto shrink collagen tissue in the dermis in an effective manner thatprevents the energy from affecting the outer layer of skin.

One aspect of the invention provides systems and methods for applyingelectromagnetic energy to skin. The systems and methods include acarrier and an array of electrodes on the carrier, which are connectableto a source of electromagnetic energy to apply the electromagneticenergy. The devices and methods described herein can also be used totreat tissue masses such as tumors, varicose veins, or other tissueadjacent to the surface of tissue.

The devices and methods described herein may provide electrode arraysthat penetrate tissue at an oblique angle or at a normal angle asdiscussed below. In addition, in those variations where the electrodearray enters at an oblique angle, the device may include a coolingsurface that directly cools the surface area of tissue adjacent to thetreated region of tissue. The cooling methods and apparatus describedherein may be implemented regardless of whether the electrodes penetrateat an oblique angle or not.

According to this aspect of the invention, a faceplate on the carrier ortreatment unit covers the array of electrodes. Faceplate can be anon-conducting material and may or may not conform to the outer surfaceof tissue.

An interior chamber is formed behind the faceplate and contains anelectrode plate. The electrode plate can move within the chamber toallow movement of the electrodes through openings in the faceplate. Itis noted however, that variations of the invention may or may not have afaceplate and/or an electrode plate.

Methods described herein include methods for applying energy to tissuelocated beneath a surface layer of the tissue by providing an energytransfer unit having a faceplate with a plurality of openings and aplurality of electrodes moveable through the faceplate. In operation amedical practitioner can place the faceplate in contact with the surfacelayer of tissue then draw and maintain the surface layer of tissueagainst the openings in the faceplate. Subsequently, or simultaneouslyto this act, the medical practitioner can advance the electrodes throughthe surface tissue and into the tissue and apply energy with a portionof the electrode beneath the skin to create a thermal injury to tissuebeneath the skin.

The number of openings may match the number of electrodes.Alternatively, there may be additional openings in the treatment unit tomaintain a vacuum with the tissue and/or allow movement of theelectrodes within the chamber.

Variations of the invention include movement of the electrodes by use ofa spring. The spring provides a spring force to move the electrodes at avelocity that allows for easier insertion of the electrode array intotissue.

Alternatively, or in combination, the electrodes may be coupled to anadditional source of energy that imparts vibration in the electrodes(e.g., an ultrasound energy generator). The same energy source may beused to generate the thermal effect in the dermis.

The methods and devices described herein may also use features tofacilitate entry of the electrodes into tissue. For example, the surfacetissue may be placed in traction prior to advancing electrodes throughthe surface tissue. The electrodes can comprise a curved shape. Whereadvancing the curved electrodes through tissue comprises rotating theelectrodes into tissue.

The power supply for use with the systems and methods described hereinmay comprise a plurality of electrode pairs, each electrode paircomprising a mono-polar or hi-polar configuration. Each electrode pairof the system may be coupled to an independent channel of a power supplyor independent power supplies. Such configurations permit improvedcontrolled delivery of energy to the treatment site.

Another variation that controls delivery of energy may include spacingwhere each electrode pair at a sufficient distance from an adjacentelectrode pair to minimize formation of a cross-current path betweenadjacent electrode pairs. Moreover, the independent power supply can beconfigured to energize adjacent electrode pairs at different times.

Devices according to the principles of the present invention include anelectrode array for treating a dermis layer of tissue, the arraycomprising a faceplate comprising a plurality of openings, a pluralityof electrode pairs each pair comprising an active and a returnelectrode, where the electrode pairs extend through openings in thefaceplate, at least one electrode plate carrying the plurality ofelectrode pairs, where the electrode plate and face plate are moveablerelative to each other to allow for axial movement of the electrodepairs through the openings.

It is expressly intended that, wherever possible, the invention includescombinations of aspects of the various embodiments described herein oreven combinations of the embodiments themselves.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a representative sectional view of skin and underlyingsubcutaneous tissue;

FIG. 2A shows a sample variation of a system according to the principlesof the invention;

FIG. 2B illustrates a partial cross-sectional view of an exemplarytreatment unit where the electrode array is retained proximal to afaceplate of the device;

FIGS. 2C-2D respectively illustrates a partial cross sectional view ofan exemplary treatment unit after tissue is drawn against the unit andthe unit after the electrodes deploy into tissue;

FIG. 2E illustrates a variation of a sensor disposed on an electrode;

FIG. 2F shows an example of spacing of electrode pairs in the electrodearray to minimize current flow between adjacent electrode pairs;

FIGS. 3A to 3B show variations of introducer members that assist inplacing electrodes within tissue;

FIGS. 4A to 4C show variations of curved electrodes that pivot or rotateinto tissue;

FIGS. 5A to 5D show variations of electrodes placed at oblique angles;

FIGS. 6A to 6C show additional variations of electrode configurations;

FIGS. 7A to 7B show additional modes of contouring the treatment unit tovarying skin geometries; and

FIG. 8A shows an additional variation of a device having an array ofelectrodes adjacent to a tissue engaging surface;

FIG. 8B shows a magnified view of the electrodes and tissue engagingsurface of the device of FIG. 8A;

FIGS. 8C to 8D show an example of an electrode entering tissue at anoblique angle adjacent to a tissue engaging surface;

FIG. 8E to 8F show cooling surfaces adjacent to the electrodes;

FIG. 8G shows a variation of a device having a marking assembly;

FIGS. 9A to 9D show another variation of an electrode device with acooling system that can be placed adjacent to the electrodes;

FIGS. 10A to 10B show an additional variation of an electrode device;

FIG. 11 shows a variation of an electrode device having a user interfaceon a body portion;

FIGS. 12A-12D illustrate variations of electrodes having varyingresistance or impedance along the length of the electrode; and

FIGS. 13A to 13B show an example of an array of electrodes where anynumber of pairs of electrodes can be triggered to apply therapeuticenergy to tissue.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The systems and method discussed herein treat tissue in the human body.In one variation, the systems and methods treat cosmetic conditionsaffecting the skin of various body parts, including face, neck, andother areas traditionally prone to wrinkling, lines, sagging and otherdistortions of the skin. The methods and systems described herein mayalso have application in other surgical fields apart from cosmeticapplications.

As FIG. 1 shows, the skin 10 covers subcutaneous tissue 12 and muscletissue 14 of within the body. In the face and neck areas, the skin 10measures about 2 mm in cross section.

The skin 10 includes an external, non-vascular covering called theepidermis 16. In the face and neck regions, the epidermis measures about100 μm in cross section. The skin 10 also includes a dermis 18 layerthat contains a layer of vascular tissue. In the face and neck regions,the dermis 18 measures about 1900 μm in cross section.

The dermis 18 includes a papillary (upper) layer and a reticular (lower)layer. Most of the dermis 18 comprises collagen fibers. However, thedermis also includes various hair bulbs, sweat ducts, and other glands.The subcutaneous tissue 12 region below the dermis 18 contains fatdeposits as well as vessels and other tissue.

In most cases, when applying cosmetic treatment to the skin, it isdesirable to deliver energy the dermis layer rather than the epidermis,the subcutaneous tissue region 12 or the muscle 14 tissue. In fact,delivery of energy to the subcutaneous tissue region 12 or muscle 14 mayproduce pockets or other voids leading to further visible imperfectionsin the skin of a patient.

The application of heat to the fibrous collagen structure in the dermis18 causes the collagen to dissociate and contract along its length. Itis believed that such disassociation and contraction occur when thecollagen is heated to about 65 degree. C. The contraction of collagentissue causes the dermis 18 to reduce in size, which has an observabletightening effect. As the collagen contacts, wrinkles, lines, and otherdistortions become less visible. As a result, the outward cosmeticappearance of the skin 10 improves. Furthermore, the eventual woundhealing response may further cause additional collagen production. Thislatter effect may further serve to tighten the skin 10.

FIG. 2A illustrates a variation of a treatment system according theprinciples described herein. The treatment system 100 generally includesa treatment unit 102 having a hand-piece 110 (or other member/featurethat allows for manipulation of the system to treat tissue 10). Thetreatment unit 102 shown includes a faceplate 104 having a plurality ofelectrodes 106 (generally formed in an array) that extend from openings108 in the faceplate 104. The devices may comprise electrode arrays ofonly a single electrode pair up to considerably larger arrays.Currently, the size of the array is determined by the target region thatis intended for treatment. For example, a treatment unit 102 designedfor relatively small treatment areas may only have a single pair ofelectrodes. On the other hand, a treatment unit 102 designed for use onthe cheek or neck may have up to 10 electrode pairs. However, estimateson the size of the electrode array are for illustrative purposes only.In addition, the electrodes on any given array may be the same shape andprofile. Alternatively, a single array may have electrodes of varyingshapes, profiles, and/or sizes depending upon the intended application.

The electrodes 106 can be fabricated from any number of materials, e.g.,from stainless steel, platinum, and other noble metals, or combinationsthereof. Additionally, the electrode may be placed on a non-conductivemember (such as a polymeric member). In any case, the electrode 106 maybe fastened to the electrode plate by various means, e.g., by adhesives,by painting, or by other coating or deposition techniques.

Additionally, the treatment unit 102 may or may not include an actuator128 for driving the electrode array 126 from the faceplate 104.Alternative variations of the system 100 include actuators driven by thecontrol system 114.

The number of electrodes 106 in the array may vary as needed for theparticular application. Furthermore, the array defined by the electrodes106 may have any number of shapes or profiles depending on theparticular application. As described in additional detail herein, inthose variations of the system 100 intended for skin resurfacing, thelength of the electrodes 106 is generally selected so that the energydelivery occurs in the dermis layer of the skin 10 while the spacing ofelectrodes 106 may be selected to minimize flow of current betweenadjacent pairs of electrodes.

When treating the skin, it is believed that the dermis should be heatedto a predetermined temperature condition, at or about 65 degree C.,without increasing the temperature of the epidermis beyond 47 degree C.Since the active area of the electrode designed to remain beneath theepidermis, the present system applies energy to the dermis in atargeted, selective fashion, to dissociate and contract collagen tissue.By attempting to limit energy delivery to the dermis, the configurationof the present system also minimizes damage to the epidermis.

The system 10 also includes an energy supply unit 114 coupled to thetreatment unit 102 via a cable 112 or other means. The energy supplyunit 114 may contain the software and hardware required to controlenergy delivery. Alternatively, the CPU, software and other hardwarecontrol systems may reside in the hand piece 110 and/or cable 112. It isalso noted that the cable 112 may be permanently affixed to the supplyunit 114 and/or the treatment unit 102. The energy supply unit may be aRF energy unit. Additional variations of energy supply units may includepower supplies to provide thermal energy, ultrasound energy, laserenergy, and infrared energy.

The energy supply unit 114 may also include an input/output (I/O) devicethat allows the physician to input control and processing variables, toenable the controller 114 to generate appropriate command signals. TheI/O device can also receive real time processing feedback informationfrom one or more sensors 98 associated with the device, for processingby the controller 114, e.g., to govern the application of energy and thedelivery of processing fluid. The I/O device may also include a display54, to graphically present processing information to the physician forviewing or analysis.

In some variations, the system 100 may also include an auxiliary unit116 (where the auxiliary unit may be a vacuum source, fluid source,ultrasound generator, medication source, etc.) Although the auxiliaryunit is shown to be connected to the energy supply, variations of thesystem 100 may include one or more auxiliary units 116 where each unitmay be coupled to the power supply 114 and/or the treatment unit 102.

FIG. 2B illustrates a cross sectional view of a variation of a treatmentunit 102 according to the systems described herein. As shown, thetreatment unit 102 includes the hand piece body 110 that houses theelectrode array 126 on an electrode plate 118. Naturally, the hand piece110 or treatment unit 102 may have any shape that accommodates ease ofuse.

FIG. 2B also shows the electrode array 126 being withdrawn behind thefaceplate 104. In the illustrated variation, the treatment unit 102includes a spring release lever or trigger 124. As described below, thespring release trigger 124 can be used to actuate a spring 130 (a coiledspring or other similar structure) to drive the electrode array 126through openings 108 in the faceplate 104. Driving the electrode array126 with the spring-force increases the force of the electrodes as theyapproach tissue and facilitates improved penetration of the tissue bythe electrodes. Although the inventive system may not include such aspring force, the absence of such a feature may require the medicalpractitioner to apply excessive force to the entire treatment unit 102when trying to insert the electrodes due to a “bed-of-nails” effect.

FIG. 2C illustrates the treatment unit 102 as it is placed againsttissue 10. In this variation, a vacuum source (not shown) may be appliedto the unit 102 to draw the tissue 10 against the faceplate 104.Typically, the vacuum pulls the tissue in through the openings 108 onthe faceplate 104. Variations of the device include additional openingsin the faceplate in addition to openings that allow passage of theelectrodes. This latter configuration permits application of a vacuum asthe electrodes penetrate the tissue.

By drawing tissue against the device or faceplate, the medicalpractitioner may better gauge the depth of the treatment. For example,given the relatively small sectional regions of the epidermis, dermis,and subcutaneous tissue, if a device is placed over an uneven contour oftissue, one electrode pair may be not be placed at the sufficient depth.Accordingly, application of energy in such a case may cause a burn onthe epidermis. Therefore, drawing tissue to the faceplate of the deviceincreases the likelihood of driving the electrodes to a uniform depth inthe tissue.

Although not shown, the electrode plate 118 may contain apertures orother features to allow distal movement of the plate 118 and electrodes106 during the application of a vacuum.

FIG. 2D illustrates deployment of the electrode array 126 into thetissue 10. Although not shown, in variations of the device suited forcosmetic applications, the length of the electrodes 106 will be chose toplace the active region of the electrode (i.e., the region that conductselectricity) within the dermis. Again, the depth of the electrodes mayvary depending upon the region of the body intended for treatment. Inone variation, the electrodes 106 may be driven into the tissue as faras possible to ensure complete contact between the faceplate 104 and thesurface of the skin. Subsequently, the electrode may be withdrawn apredetermined distance to place the active portion of the electrode inthe proper location.

FIG. 2E illustrates an example of an electrode 106 having a sensor 98.The sensor may be any device that monitors temperature of the tissue,impedance, or other characteristic. Additionally, more than one sensor98 may be used on a single electrode, on an electrode array, on thefaceplate or any combination thereof.

In variations of the present system, the electrodes 106 can beconfigured to individually rotate, vibrate (e.g., via ultrasonicenergy), or cycle in an axial direction, where such actions are intendedto lower the overall insertion force required by the medicalpractitioner to place the electrodes within tissue. [00701 Theelectrodes 106 are arranged in a pair configuration. In a bi-polarconfiguration one electrode 120 serves a first pole, while the secondelectrode 122 serves as the second pole (it is also common to refer tosuch electrodes as the active and return electrodes). The spacing ofelectrode pairs 106 is sufficient so that the pair of electrodes 120,122 is able to establish a treatment current path therebetween for thetreatment of tissue. However, adjacent electrode pairs 106 will bespaced sufficiently to minimize the tendency of current flowing betweenthe adjacent pairs. Typically, each electrode pair 106 is coupled to aseparate power supply or to a single power supply having multiplechannels for each electrode pair.

The benefit of such a configuration is that, when compared toconventional treatments, the amount of power required to induce heatingin the target tissue is much reduced. For example, because theelectrodes are spaced to provide heating across the electrode pairs atthe target tissue, each channel of the system may provide 1 watt ofenergy to produce the desired temperature increase at the site. Incontrast, if a treatment system delivered energy over the entireelectrode array, a much greater amount of energy is required to generatethe desired temperature over the larger surface area of tissue.Moreover, the energy demand is less because the treatment applies energydirectly to the target tissue rather than though additional layers oftissue.

In one variation of the device, it is believed that a desirable spacingof the first and second electrode poles is between 1 and 3 mm, while adesirable spacing of electrode pairs is between 5 and 6 mm. In oneexample, the described configuration allowed for each independentchannel to deliver no more than 1 watt to deliver acceptable tissuetreatment results. Obviously, the power supply may be configured todeliver greater amounts of energy as needed depending on theapplication.

FIG. 2F illustrates the electrode array 126 when deployed within tissue10. As noted above, variations of the device include electrode pairs120, 122 provided in a bi-polar configuration where each pair is coupledto a separate power supply or separate channel of a power supply. Asshown, this configuration permits flow of current 132 between the twoelectrodes in the electrode pair rather than between adjacent pairs.Again, the invention is not limited to such a configuration and may bemonopolar, and/or have electrode spacing that permits flow of currentbetween several electrodes on the electrode array.

The ability to control each electrode pair on a separate channel fromthe power supply provides additional benefits based on the impedance orother characteristic of the tissue being treated. For example, eachelectrode pair may include a thermocouple to separately monitor eachtreatment site; the duration of the energy treatment may be controlleddepending on the characteristics of the surrounding tissue; selectiveelectrode pairs may be fired rather than all of the electrode pairsfiring at once (e.g., by firing electrode pairs that are located onopposite ends of the electrode plate one can further minimize the chancethat a significant amount of current flows between the separateelectrode pairs.) Naturally, a number of additional configurations arealso available depending on the application. Additional variations ofthe device may include electrode pairs that are coupled to a singlechannel of a power supply as well.

The present systems may deliver energy based upon sensing tissuetemperature conditions as a form of active process feedback control.Alternatively, the systems may monitor changes in impedance of thetissue being treated and ultimately stop the treatment when a desiredvalue is obtained. Yet another mode of energy delivery is to provide atotal maximum energy over a duration of time.

As noted herein, temperature or other sensing may be measured beneaththe epidermis in the dermis region. Each probe or electrode may includea sensor or the sensor may be placed on a structure that penetrates thetissue but does not function as an energy delivery electrode. In yetanother variation, the sensors may be a vertically stacked array ofsensors to provide data along a depth or length of tissue.

FIG. 3A illustrates an aspect for use with the variations of the devicesdescribed herein. In this example, the electrodes 120, 122 include anintroducer member 134 that places tissue 10 in a state of tension (alsocalled “traction”). In this variation the introducer 134 is locatedabout each opening 108 in the faceplate 104. However, alternatevariations of the device include introducer members placed directly onthe electrode.

As shown, once the introducer member 134 engages tissue 10, the tissuefirst elastically deforms as shown. Eventually, the tissue can no longerdeflect and is placed in traction by the introducer members 134. As aresult, the electrodes 120, 122 more readily penetrate the tissue.

FIG. 3B illustrates another variation of the introducer member 134 thatis tapered inwards toward the electrodes so that the opening at thedistal end closely fits around the electrode.

In those variations of systems according to the present invention, ifthe electrodes engage the tissue without the introducer members, thenthe electrodes themselves may cause plastic deformation of the surfacetissue. Such an occurrence increases the force a medical practitionermust apply to the device to deploy the electrodes in tissue.

FIG. 4A shows another variation of an aspect for use with variations ofthe inventive device where the electrodes 120, 122 in the array have acurved or arcuate profile. When actuated, the electrodes 120, 122 rotateinto the tissue 10. Such a configuration may rely on a cam typemechanism (e.g., where the electrode plate and electrode rely on acam-follower type motion to produce rotation of the electrodes).

The electrodes 120, 122 may have a curved shape similar to that ofsuture needles, and/or may be fabricated from a shape memory alloy thatis set in a desired curve. As shown in FIG. 4B, as the electrodes 120,122 rotate into tissue, the rotational movement substantially causes atransverse force within the tissue rather than a normal force to thetissue. Accordingly, there is less tissue deformation as the electrodespenetrate the tissue allowing for ease of insertion.

FIG. 4B illustrates the first and second electrodes 120,122 withintissue. The depth of insertion of these electrodes may be controlled byselecting a proper combination of electrode length and radius ofcurvature.

FIG. 4C illustrates another variation of curved electrodes. In thisvariation, the electrodes may be configured to overlap. Such overlapresults in the active electrode area being close in proximity to bettercontrol the current path between electrodes.

FIG. 5A shows another electrode configuration for use with variations ofthe inventive device. As illustrated, the electrodes 120, 122 may beplaced at an oblique angle A relative to the face plate 104 or treatmentunit 102. FIG. 5A illustrates the condition as the electrodes 120, 122approach the tissue 10. FIG. 5B shows the electrodes 120, 122 beingadvanced towards each other as are placed in tissue 10. The angle of theelectrodes 120, 122 creates a lateral or transverse force on the tissue10 that serves to place a portion of the tissue in a state of traction.

FIG. 5C shows a variation in which the electrodes 120, 122 approach thetissue at an oblique angle A but where the electrodes are directed awayfrom one another. Again, this configuration provides an opposing forceon the tissue 10 between the electrodes as the electrodes 120, 122penetrate the tissue. FIG. 5D shows the electrodes after they areinserted. Again, such a configuration reduces the force required toplace the electrodes within tissue.

In the above configuration, it may be necessary to have one or moreelectrode plates 104 as an electrode moves along two or more dimensions.However, various additional configurations may be employed to producethe desired effects.

FIGS. 6A-6C illustrate additional variations of electrodes 106 for usewithin the current devices. In these cases, the electrode 106 rotates asit penetrates tissue. FIG. 6A shows a rotating blade-type configurationwhere part or all of the blade may have an exposed conductive surfacefor establishing a current path. Alternatively, a single blade may haveboth the poles of the circuit such that the electrode pair is on asingle electrode.

FIG. 6B illustrates a cork-screw or helical type electrode. FIG. 6Cshows an electrode 106 having a threaded portion 132.

Variations of the present device may include treatment units havingfeatures to allow for treatment of contoured surfaces. For example, FIG.7A illustrates a contoured faceplate 104. The contour of the faceplate104 may be selected depending on the intended area of treatment. Forexample, a medical practitioner may have a range of contoured surfacesand could choose one depending on the shape of patient's face. In theillustrated variation, the electrode plate 118 may also be contoured(e.g., to match the faceplate or otherwise). As shown, the electrodes120, 122 can be sized such that a uniform length extends beyond thefaceplate. However, variations also include electrodes having varyinglengths that extend from the faceplate.

FIG. 7B illustrates a variation having a double spring configuration.The first spring 134 is placed between the faceplate 104 and theelectrode plate 118. One or more additional springs are placed on theelectrodes 120, 122. Again, such a configuration assists in placing thefaceplate 104 against tissue as well as adjusting for contours in theskin surface.

FIG. 8A illustrates another variation of a treatment unit 200 for use inaccordance with the principles discussed herein. In this variation, theunit 200 includes a body portion 202 from which a cannula or introducermember 204 extend at an oblique angle relative to a tissue engagementsurface 206. As described below, the ability to insert the electrodes(not shown) into the tissue at an oblique angle increases the treatmentarea and allows for improved cooling at the tissue surface. Although thevariation only shows a single array of introducers for electrodes,variations of the invention may include multiple arrays of electrodes.In addition, the devices and systems described below may be combinedwith the features described herein to allow for improved penetration oftissue. The devices of the present invention may have an angle A of 15degrees. However, the angle may be anywhere from ranging between 5 and85 degrees.

Although the introducer member 204 is shown as being stationary,variations of the device include introducer members that are slidable onthe electrodes. For example, to ease insertion of the electrode, theelectrode may be advanced into the tissue. After the electrode is in thetissue, the introducer member slides over the electrode to a desiredlocation. Typically, the introducer member is insulated and effectivelydetermines the active region of the electrode. In another variationusing RF energy, the introducer member may have a return electrode onits tip. Accordingly, after it advances into the tissue, application ofenergy creates current path between the electrode and the returnelectrode on the introducer.

The body 202 of the electrode device 200 may also include a handleportion 208 that allows the user to manipulate the device 200. In thisvariation, the handle portion 208 includes a lever or lever means 210that actuates the electrodes into the tissue (as discussed in furtherdetail below).

As discussed above, the electrode device 200 can be coupled to a powersupply 114 with or without an auxiliary unit 116 via a connector orcoupling member 112. In some variations of the device, a display or userinterface can be located on the body of the device 200 as discussedbelow.

FIG. 8B illustrates a partial side view of the electrodes 212 and tissueengaging surface 206 of the electrode device of FIG. 8A. As shown, theelectrodes 212 extend from the device 200 through the cannula 204. Inalternate variations, the electrodes can extend directly from the bodyof the device or through extensions on the device.

As shown, the electrodes 212 are advanceable from the body 202 (in thiscase through the introducers 204) in an oblique angle A as measuredrelative to the tissue engagement surface 206. The tissue engagementsurface 206 allows a user to place the device on the surface of tissueand advance the electrodes 212 to the desired depth of tissue. Becausethe tissue engagement surface 206 provides a consistent starting pointfor the electrodes, as the electrodes 212 advance from the device 202they are driven to a uniform depth in the tissue.

For instance, without a tissue engagement surface, the electrode 212 maybe advanced too far or may not be advanced far enough such that theywould partially extend out of the skin. As discussed above, either casepresents undesirable outcomes when attempting to treat the dermis layerfor cosmetic affects. In cases where the device is used for tumorablation, inaccurate placement may result in insufficient treatment ofthe target area.

FIG. 8C illustrates a magnified view of the electrode entering tissue 20at an oblique angle A with the tissue engaging surface 206 resting onthe surface of the tissue 20. As is shown, the electrode 212 can includean active area 214. Generally, the term “active area” refers to the partof the electrode through which energy is transferred to or from thetissue. For example, the active area could be a conductive portion of anelectrode, it can be a resistively heated portion of the electrode, oreven comprise a window through which energy transmits to the tissue.Although this variation shows the active area 214 as extending over aportion of the electrode, variations of the device include electrodes212 having larger or smaller active areas 214.

In any case, because the electrodes 212 enter the tissue at an angle A,the resulting region of treatment 152, corresponding to the active area214 of the electrode is larger than if the needle were drivenperpendicular to the tissue surface. This configuration permits a largertreatment area with fewer electrodes 212. In addition, the margin forerror of locating the active region 214 in the desired tissue region isgreater since the length of the desired tissue region is greater atangle A than if the electrode were deployed perpendicularly to thetissue.

As noted herein, the electrodes 212 may be inserted into the tissue ineither a single motion where penetration of the tissue and advancementinto the tissue are part of the same movement or act. However,variations include the use of a spring mechanism or impact mechanism todrive the electrodes 212 into the tissue. Driving the electrodes 212with such a spring-force increases the momentum of the electrodes asthey approach tissue and facilitates improved penetration into thetissue. As shown below, variations of the devices discussed herein maybe fabricated to provide for a dual action to insert the electrodes. Forexample, the first action may comprise use of a spring or impactmechanism to initially drive the electrodes to simply penetrate thetissue. Use of the spring force or impact mechanism to drive theelectrodes may overcome the initial resistance in puncturing the tissue.The next action would then be an advancement of the electrodes so thatthey reach their intended target site. The impact mechanism may bespring driven, fluid driven or via other means known by those skilled inthe art. One possible configuration is to use an impact or springmechanism to fully drive the electrodes to their intended depth.

FIG. 8D illustrates an example of the benefit of oblique entry when thedevice is used to treat the dermis 18. As shown, the length of thedermis 18 along the active region 214 is greater than a depth of thedermis 18. Accordingly, when trying to insert the electrode in aperpendicular manner, the shorter depth provides less of a margin forerror when trying to selectively treat the dermis region 18.

Inserting the electrode at angle A also allows for direct cooling of thesurface tissue. As shown in FIG. 8C, the area of tissue on the surface156 that is directly adjacent or above the treated region 152 (i.e., theregion treated by the active area 214 of the electrode 212) is spacedfrom the entry point by a distance or gap 154. This gap 154 allows fordirect cooling of the entire surface 156 adjacent to the treated region152 without interference by the electrode or the electrode mountingstructure. In contrast, if the electrode were driven perpendicularly tothe tissue surface, then cooling must occur at or around theperpendicular entry point.

FIG. 8E illustrates one example of a cooling surface 216 placed on bodystructure or tissue 20. As shown, the electrode 212 enters at an obliqueangle A such that the active region 214 of the electrode 212 is directlyadjacent or below the cooling surface 216. In certain variations, thecooling surface may extend to the entry point (or beyond) of theelectrode 212. However, it is desirable to have the cooling surface 216over the electrode's active region 214 because the heat generated by theactive region 212 will be greatest at the surface 156. In somevariations, devices and methods described herein may also incorporate acooling source in the tissue engagement surface.

The cooling surface 216 may be any cooling mechanism known by thoseskilled in the art. For example, it may be a manifold type block havingliquid or gas flowing through for convective cooling. Alternatively, thecooling surface 216 may be cooled by a thermoelectric cooling device(such as a fan or a Peltier-type cooling device). In such a case, thecooling may be driven by energy from the electrode device thuseliminating the need for additional fluid supplies. One variation of adevice includes a cooling surface 216 having a temperature detector 218(thermocouple, RTD, optical measurement, or other such temperaturemeasurement device) placed within the cooling surface. The device mayhave one or more temperature detectors 218 placed anywhere throughoutthe cooling surface 216 or even at the surface that contacts the tissue.

In one application, the cooling surface 216 is maintained at or nearbody temperature. Accordingly, as the energy transfer occurs causing thetemperature of the surface 156 to increase, contact between the coolingsurface 216 and the tissue 20 shall cause the cooling surface toincrease in temperature as the interface reaches a temperatureequilibrium. Accordingly, as the device's control system senses anincrease in temperature of the cooling surface 216 additional coolingcan be applied thereto via increased fluid flow or increased energysupplied to the Peltier device.

While the cooling surface may comprise any commonly known thermallyconductive material, metal, or compound (e.g., copper, steel, aluminum,etc.). Variations of the devices described herein may incorporate atranslucent or even transparent cooling surface. In such cases, thecooling device will be situated so that it does not obscure a view ofthe surface tissue above the region of treatment.

In one variation, the cooling surface can include a single crystalaluminum oxide (Al₂O₃). The benefit of the single crystal aluminum oxideis a high thermal conductivity optical clarity, ability to withstand alarge temperature range, and the ability to fabricate the single crystalaluminum oxide into various shapes. A number of other opticallytransparent or translucent substances could be used as well (e.g.,diamond, other crystals or glass).

FIG. 8F illustrates another aspect for use with variations of thedevices and methods described herein. In this variation, the device 200includes two arrays of electrodes 212, 222. As shown, the firstplurality 212 is spaced evenly apart from and parallel to the secondplurality 222 of electrodes. In addition, as shown, the first set ofelectrodes 212 has a first length while the second set of electrodes 222has a second length, where the length of each electrode is chosen suchthat the sets of electrodes 212, 222 extend into the tissue 20 by thesame vertical distance or length 158. Although only two arrays ofelectrodes are shown, variations of the invention include any number ofarrays as required by the particular application. In some variations,the lengths of the electrodes 212, 222 are the same. However, theelectrodes will be inserted or advanced by different amounts so thattheir active regions penetrate a uniform amount into the tissue. Asshown, the cooling surface may include more than one temperaturedetecting element 218.

FIG. 8F also illustrates a cooling surface 216 located above the activeregions 214, 224 of the electrodes. In such a variation, it may benecessary for one or more of the electrode arrays to pass through aportion of the cooling surface 216. Alternative variations of the deviceinclude electrodes that pass through a portion of the cooling device(such as the Peltier device described below).

FIG. 8G shows an aspect for use with methods and devices of theinvention that allows marking of the treatment site. As shown, thedevice 200 may include one or more marking lumens 226, 228 that arecoupled to a marking ink 220. During use, a medical practitioner may beunable to see areas once treated. The use of marking allows thepractitioner to place a mark at the treatment location to avoidexcessive treatments. As shown, a marking lumen 226 may be placedproximate to the electrode 212. Alternatively, or in combination,marking may occur at or near the cooling surface 216 since the coolingsurface is directly above the treated region of tissue. The markinglumens may be combined with or replaced by marking pads. Furthermore,any type of medically approved dye may be used to mark Alternatively,the dye may comprise a substance that is visible under certainwavelengths of light. Naturally, such a feature permits marking andvisualization by the practitioner given illumination by the proper lightsource but prevents the patient from seeing the dye subsequent to thetreatment.

FIG. 9A illustrates a variation of a device 200 that may incorporate theaspects described herein. As shown, the device 200 includes a bodyportion 202 having a handle 208 and an actuating trigger or lever 210.The device 200 couples power supply and other necessary auxiliarycomponents though they are not illustrated. In this variation, theelectrodes may be placed behind an electrode covering 230. The covering230 may be purely cosmetic or may function as the introducers discussedabove. In the illustrated variation, the cooling surface 216 is coupledto a Peltier cooling device 234. Although the cooling surface 216 isshown as being retracted from the tissue engagement surface 206, thecooling surface may be lowered when necessary to maintain the surfacetissue during treatment. As noted above, variations of the device mayinclude an impact means to drive the electrodes into tissue. In thisvariation, the device 200 includes a reset knob 232 so that thepractitioner may re-engage the impact mechanism or spring mechanismbetween treatments. Alternatively, the reset-knob may be configured towithdraw the electrodes from the tissue and into the device aftertreatment.

FIG. 9B illustrates a cross-sectional side view of the device 200 ofFIG. 9A. As shown, the lever 210 is coupled to an electrode base orelectrode plate 228 to drive the electrodes 212 into tissue. In thisvariation, the actuating assembly also includes an impact mechanism 236that, at least, initially drives the electrodes 212 into tissue toovercome the resistance when penetrating the surface of tissue.

FIG. 9C illustrates a side view of the device 200 of FIG. 9A when thecooling surface 216 is parallel to the tissue engaging surface 206 anddirectly above the electrodes 212 when advanced from the device body202. In this variation, the electrodes 212 at least partially extendthrough the cooling surface 216. However, the cooling surface 216 isstill able to make direct contact with a surface of tissue directlyabove the active area of the electrodes.

FIG. 9C also shows a Peltier cooling device 234 coupled to the coolingsurface 216. As noted herein, any number of cooling sources may be used.However, in this variation, the Peltier cooling device 234 eliminatesthe need for a fluid source. In some cases, the cooling device 234 canbe powered using the same power supply that energizes the electrodes212. Such a configuration provides a more compact design that is easierfor a medical practitioner to manipulate.

FIG. 9D illustrates a bottom view of the device 200 of FIG. 9C. As shownthe electrodes 212 directly below the cooling surface 216 when extendedfrom the body of the device 202.

FIG. 10A illustrates another variation of an electrode device 200. Inthis variation, the lever 210 or actuator is on the top of the handleportion 208. The lever 210 may be manually operated in that the medicalpractitioner advances the lever 210 to advance the electrodes 212 intotissue. Alternatively, or in combination a spring mechanism or even asource of compressed gas (stored in the body 202 or coupled via aconnector 112) may be used to drive the electrodes 212 from theintroducers 204 and into the tissue.

FIG. 10B illustrates a side view of the device 200 of FIG. 10A. Asshown, the tissue engaging surface 206 is parallel to the ends of theintroducers 204. Accordingly, to deliver the electrodes 212, 222 to auniform depth, the lengths of the electrodes 212, 222 may varyaccordingly.

FIG. 11 shows a variation of a device 200 having additional aspects forcombination with the methods and devices described herein. As shown, thedevice 200 may include an electrode covering 230 to shield theelectrodes from damage or view. In the latter case, hiding theelectrodes from view may be desirable for additional patient comfort.FIG. 11 also illustrates a user interface 240. The user interface 240may display such information as whether the system is ready fortreatment, the temperature of the cooling surface, the duration of theparticular treatment, the number of treatments or any other informationregarding the procedure or patient.

The variations in FIGS. 10A-11 are shown without a cooling surface.However, incorporating cooling surfaces with the respective devicebodies is within the scope of this disclosure.

FIGS. 12A-12D illustrate variations of electrodes for use with thesystems and methods described herein. Depending upon the application, itmay be desirable to provide an electrode 212 that has a variableresistance along the active region of the electrode 212. FIGS. 12A-12Dillustrate a partial example of such electrodes. As shown in FIG. 12Aand 12B, an electrode may have concentric or spiral bands that createvarying ranges of impedance 242, 244, 246, 248, and 250 along theelectrode 212. In addition, as shown in FIG. 12C, the electrode 212 mayhave regions 242, 244, 246, and 248 along the electrode of varyingresistance. FIG. 12D illustrates a similar concept where the regions ofresistance 242, 244, 246 run in longitudinal stripes along the electrode212. These configurations may be fabricated through spraying, dipping,plating, anodizing, plasma treating, electro-discharge, chemicalapplications, etching, etc.

FIGS. 13A-13B illustrate examples of system configurations that can beincorporated into any conventional electrode array or into the devicesdescribed above using RF energy. As shown, in this example the electrodearray 262 comprises a 3×6 array of electrode. Each electrode in thearray 262 is configured to energize separately. This configurationprovides the ability of any given pair of electrodes to form a circuitfor treating tissue. In one example, in the variation of FIG. 13A, thepower supply energizes adjacent electrode pairs 264, 266. Thisconfiguration generates the smallest treatment area in the electrodearray 262. FIG. 13B illustrates a situation where the farthest electrodepairs 264, 266 within the array 262 are triggered to form a current path268. One benefit of this configuration is that a single electrode arraymay form a number of patterns based on various combinations of pairsthat may be formed in the array. The array may be able to provide adenser treatment or more uniform tissue heating. The treatment candeliver targeted therapy to key areas of tissue. In one variation, theelectrode array may trigger various pairs sequentially during a singleinsertion.

Although the systems described herein may be used by themselves, theinvention includes the methods and devices described above incombination with moisturizer, ointments, etc. that increase theresistivity of the epidermis. Accordingly, prior to the treatment, themedical practitioner can prepare the patient by increasing theresistivity of the epidermis. During the treatment, because of theincreased resistivity of the epidermis, energy would tend to flow in thedermis.

The above variations are intended to demonstrate the various examples ofembodiments of the methods and devices of the invention. It isunderstood that the embodiments described above may be combined or theaspects of the embodiments may be combined in the claims.

1. A method for applying energy to a region of tissue, comprising:placing a tissue engaging surface of an electrode device against asurface of the tissue, where the electrode device comprises at least oneelectrode extending at an oblique angle relative to the tissue engagingsurface; inserting the electrode obliquely into the tissue at an entrypoint such that a surface of the tissue directly above electrode isspaced from the entry point of the electrode and such that the tissueengaging surface does not extend over the surface of tissue directlyabove an active region of the electrode; and applying energy to tissueby delivering energy to the active region the of electrode.
 2. Themethod of claim 1, further comprising placing a cooling surface adjacentto the entry point, where the cooling surface directly cools theexterior surface of the tissue directly above the active region of eachof the electrodes.
 3. The method of claim 2, where the cooling surfaceis visually transparent.
 4. The method of claim 2, where the coolingsurface is visually translucent.
 5. The method of claim 2, where thecooling surface comprises a silica based glass.
 6. The method of claim2, where the cooling surface comprises a single crystal aluminum oxidematerial.
 7. The method of claim 2, where the cooling surface comprisesa material selected from the group consisting of steel, aluminum, andcopper.
 8. The method of claim 2, where the electrode passes through aportion of the cooling surface when inserting the electrodes into thetissue.
 9. The method of claim 2, where inserting the electrodescomprises first applying an impact force to the electrode such that theelectrode penetrates the tissue and subsequently, advancing theelectrode farther into the tissue.
 10. The method of claim 2, furthercomprising: placing a portion of the surface of the tissue that isadjacent to each electrode in a state of traction as the electrodes areinserted into the tissue; advancing at least one of the electrodesthrough the surface layer; applying energy to at least one of theelectrodes to create a thermal injury to tissue beneath the surface ofthe tissue.
 11. The method of claim 2, where each electrode extendsthrough an opening in an introducer member, where pressing theintroducer member against the surface of the tissue places the surfaceof the tissue in traction.
 12. The method of claim 2, where applyingenergy comprises using a power supply configured to energize adjacentelectrodes at different times.
 13. The method of claim 2, where theregion of tissue comprises tissue selected from the group consisting ofthe dermis, a tumor, and a blood vessel